Light emitting device and light emitting device package

ABSTRACT

Disclosed are a light emitting device and a light emitting device package. The light emitting device includes a first electrode, a light emitting structure including a first semiconductor layer, an active layer, and a second semiconductor layer on the first electrode, a nano-tube layer including a plurality of carbon nano tubes on the light emitting structure, and a second electrode on the light emitting structure.

The present application is a Continuation of co-pending U.S. patentapplication Ser. No. 13/033,264 filed on Feb. 23, 2011, which claimspriority to Korean Patent Application No. 10-2010-0020755 filed on Mar.9, 2010, the disclosures of which are hereby incorporated by referencein its entirety.

BACKGROUND

The embodiment relates to a light emitting device and a light emittingdevice package.

Light emitting diodes (LEDs) are a kind of semiconductor devices thatconvert electric energy into light. The LED is advantageous as comparedwith conventional light sources, such as a fluorescent lamp or a glowlamp, in terms of power consumption, life span, response speed, safetyand environmental-friendly requirement. In this regard, various studieshave been performed to replace the conventional light sources with theLEDs. The LEDs are increasingly used as light sources for lightingdevices such as various lamps, liquid crystal displays, electricsignboards, and street lamps.

SUMMARY

The embodiment provides a light emitting device having a novel structureand a light emitting device package.

The embodiment provides a light emitting device capable of improvinglight extraction efficiency.

According to the embodiment, a light emitting device includes a lightemitting structure including a first semiconductor layer, an activelayer, and a second semiconductor layer, a nano-tube layer includingcarbon nano tubes on the light emitting structure, a first electrode onone of the first and second semiconductor layers, and a second electrodeon the other of the first and second semiconductor layers.

According to the embodiment, a light emitting device includes a firstelectrode including a support member having conductivity, a lightemitting structure including a first semiconductor layer, an activelayer, and a second semiconductor layer on the first electrode, anano-tube layer on the second semiconductor layer to partially exposethe second semiconductor layer, and a second electrode on at least oneof the second semiconductor layer and the nano-tube layer.

According to the embodiment, a light emitting device includes asubstrate, a light emitting structure including a first semiconductorlayer, an active layer, and a second semiconductor layer on thesubstrate, a first electrode on the first semiconductor layer, a nanotube layer on the second semiconductor layer, a second electrode on thenano tube layer, a passivation layer surrounding the light emittingstructure, and a current blocking layer between the second semiconductorlayer and the nano tube layer corresponding to the second electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view showing a light emitting deviceaccording to a first embodiment;

FIGS. 2 to 11 are view showing the manufacturing process of the lightemitting device according to the first embodiment;

FIG. 12 is a side sectional view showing a light emitting deviceaccording to a second embodiment;

FIG. 13 is a side sectional view showing a light emitting deviceaccording to a third embodiment;

FIG. 14 is a side sectional view showing a light emitting deviceaccording to a fourth embodiment;

FIG. 15 is a side sectional view showing a light emitting deviceaccording to a fifth embodiment;

FIG. 16 is a side sectional view showing a light emitting device packageincluding the light emitting device according to the embodiment;

FIG. 17 is an exploded perspective view showing a display apparatusaccording to the embodiment;

FIG. 18 is a view showing the display apparatus according to theembodiment; and

FIG. 19 is a perspective view showing a lighting apparatus according tothe embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the description of the embodiments, it will be understood that, whena layer (or film), a region, a pattern, or a structure is referred to asbeing “on” or “under” another substrate, another layer (or film),another region, another pad, or another pattern, it can be “directly” or“indirectly” over the other substrate, layer (or film), region, pad, orpattern, or one or more intervening layers may also be present. Such aposition of the layer has been described with reference to the drawings.

The thickness and size of each layer shown in the drawings may beexaggerated, omitted or schematically drawn for the purpose ofconvenience or clarity. In addition, the size of elements does notutterly reflect an actual size.

FIG. 1 is a side sectional view showing a light emitting device 100according to a first embodiment.

Referring to FIG. 1, the light emitting device 100 according to thefirst embodiment includes a first electrode 160, an adhesive layer 158on the first electrode 160, a reflective layer 157 on the adhesive layer158, a protection layer 155 on an outer peripheral portion of a topsurface of the reflective layer 157, an ohmic contact layer 156 on thereflective layer 157, a light emitting structure 145 formed on the ohmiccontact layer 156 and the protection layer 155 to generate light, anano-tube layer 135 on a top surface of the light emitting structure145, a passivation layer 180 on a lateral surface of the light emittingstructure 145, and a second electrode 170 on the nano-tube layer 135.

The first electrode 160 not only supports a plurality of layers thereon,but acts as an electrode. In other words, the first electrode 160 mayinclude a support member having conductivity. The first electrode 160may supply power to the light emitting structure 145 together with thesecond electrode 170.

The first electrode 160 may include at least one selected from the groupconsisting of titan (Ti), chromium (Cr), nickel (Ni), aluminum (Al),platinum (Pt), gold (Au), tungsten (W), copper (Cu), molybdenum (Mo),copper-tungsten (Cu—W), and a carrier wafer (including Si, Ge, GaAs,ZnO, SiC, SiGe, or GaN).

The thickness of the first electrode 160 may vary according to thedesign of the light emitting device 100. For example, the thickness ofthe first electrode 160 may be in the range of about 30 μm to about 500μm.

The first electrode 160 may be plated and/or deposited under the lightemitting structure 145, or may be attached in the form of a sheet, butthe embodiment is not limited thereto.

The adhesive layer 158 may be formed on the first electrode 160. Theadhesive layer 158 acts as a bonding layer and is formed under thereflective layer 157. The adhesive layer 158 contacts the reflectivelayer 157 to enhance adhesive strength between the reflective layer 157and the first electrode 160.

The adhesive layer 158 may include barrier metal or bonding metal. Forexample, the adhesive layer 158 may include at least one selected fromthe group consisting of Ti, Au, Sn, Ni, Cr, Ga, In, Bi, Cu, Ag, and Ta.

However, if the first electrode 160 is formed through a plating schemeor a deposition scheme instead of a bonding scheme, the adhesive layer158 may not be formed.

The reflective layer 157 may be formed on the adhesive layer 158. Thereflective layer 157 reflects light incident from the light emittingstructure 145 to improve the light emission efficiency of the lightemitting device 100.

The reflective layer 157 may include a material having high reflectance.The reflective layer 157 may include at least one selected from thegroup consisting of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf,or an alloy including at least two of the above materials, but theembodiment is not limited thereto. The reflective layer 157 may have amultiple layer structure including a transparent conductive materialsuch as IZO (In—ZnO), GZO (Ga—ZnO), AZO (Al—ZnO), AGZO (Al—Ga—ZnO), IGZO(In—Ga—ZnO), IZTO (indium zinc tin oxide), IAZO (indium aluminum zincoxide), IGTO (indium gallium tin oxide), or ATO (aluminum tin oxide)together with the metal. For example, the reflective layer 157 may havea multiple layer structure layer such as IZO/Ni, AZO/Ag, IZO/Ag/Ni, orAZO/Ag/Ni.

The protection layer 155 may be formed on an outer peripheral portion ofthe top surface of the reflective layer 157. In other words, theprotection layer 155 may be formed on an outer peripheral portion amongthe light emitting structure 145, the ohmic contact layer 156, and thereflective layer 157.

The protection layer 155 may include an electrical insulating materialor a material having electrical conductivity lower than that of thelight emitting structure 145. For example, the protection layer 155 mayinclude at least one selected from the group consisting of Si02, SixOy,Si3N4, SixNy, SiOxNy, Al2O3, and TiO2. In this case, the protectionlayer 155 may prevent the light emitting structure 145 from beingelectrically shorted with the first electrode 160, so that thereliability for the light emitting device 100 can be improved.

The protection layer 155 may include a metallic material representingsuperior adhesive strength. For example, the protection layer 155 mayinclude at least one selected from the group consisting of Ti, Ni, Pt,Pd, Rh, Ir and W. In this case, the protection layer 155 enhances theadhesive strength between the light emitting structure 145 and thereflective layer 157, so that the reliability for the light emittingdevice 100 can be improved. The protection layer 155 is not broken sothat fragments do not occur in a laser scribing process to divide aplurality of chips in the unit of an individual chip and an LLO (LLO)process to remove the substrate when performing a chip separationprocess. Accordingly, the reliability for the light emitting device 100can be improved. In addition, when the protection layer 155 makes ohmiccontacts with the first conductive semiconductor layer 150, currentflows through the protection layer 155. Accordingly, the active layer149 overlapping with the protection layer 155 in a perpendiculardirection may generate light, so that the light emission efficiency ofthe light emitting device 100 can be more improved. For example, if thefirst conductive semiconductor layer 150 is a P type semiconductorlayer, the protection layer 155 may include Ti, Ni, or W making ohmiccontact with respect to the P type semiconductor, but the embodiment isnot limited thereto.

The ohmic contact layer 156 makes ohmic contact with a first conductivesemiconductor layer 150 of the light emitting structure 145, so thatpower can be smoothly supplied to the light emitting structure 145.

In detail, the ohmic contact layer 156 may selectively includetransparent conductive material or metal. The ohmic contact layer 156may be realized in a single layer structure or a multiple layerstructure by using at least one selected from the group consisting ofITO (indium tin oxide), IZO (indium zinc oxide), IZTO (indium zinc tinoxide), IAZO (indium aluminum zinc oxide), IGZO (indium gallium zincoxide), IGTO (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO(antimony tin oxide), GZO (gallium zinc oxide), IrOx, RuOx, RuOx/ITO,Ni, Ag, Ni/IrOx/Au, and Ni/IrOx/Au/ITO.

Meanwhile, if the reflective layer 157 makes ohmic contact with thelight emitting structure 145, the ohmic contact layer 156 may be notformed.

A CBL (current blocking layer) 154 may be formed on the ohmic contactlayer 156 such that the ohmic contact layer 156 contacts the firstconductive semiconductor layer 150. At least a part of the CBL 154 mayoverlap with the second electrode 170 in a vertical direction. The CBL154 blocks current supplied to the first conductive semiconductor layer150 through the ohmic contact layer 156. Accordingly, current can beblocked from being supplied to the first conductive semiconductor layer150 at the CBL 154 and in the vicinity of the CBL 154. In other words,the CBL 154 blocks current from being concentrated along the shortestpath between the first electrode 160 and the second electrode 170 asmuch as possible. In contrast, the current flows to a region between theohmic contact layer 156 and the first conductive semiconductor layer 150other than the CBL 154, so that the current can uniformly flowthroughout the whole region of the first conductive semiconductor layer150. Accordingly, the light emission efficiency can be remarkablyimproved.

Although current is prevented from flowing along the shortest pathbetween the first electrode 160 and 170 by the CBL 154, current flowingthrough the peripheral portion of the CBL 154 flows on the shortest pathbetween the first and second electrodes 160 and 170 in the firstconductive semiconductor layer 150 adjacent to the CBL 154. Accordingly,the amount of current flowing through the shortest path between thefirst electrode 160 and the second electrode 170 may be similar oridentical to the amount of current flowing in the first conductivesemiconductor layer 150 through other current paths.

The CBL 154 may include a material having electrical conductivity lowerthan that of the ohmic contact layer 156 or an electrical insulatingproperty, or forming schottky contact with respect to the firstconductive layer 150. For example, the CLB 154 may include at least oneselected from the group consisting of ITO, IZO, IZTO, IAZO, IGZO, IGTO,AZO, ATO, ZnO, SiO2, SiOx, SiOxNy, Si3N4, Al2O3, TiOx, Ti, Al, and Cr.

Meanwhile, the CBL 154 may be disposed between the ohmic contact layer156 and the first conductive semiconductor layer 150, or disposedbetween the reflective layer 157 and the ohmic contact layer 156, butthe embodiment is not limited thereto.

In addition, the CBL 154 may be formed inside a recess formed in theohmic contact layer 156, protrude from the ohmic contact layer 156, orbe formed inside a hole passing from a top surface of the ohmic contactlayer 156 to the bottom surface thereof, but the embodiment is notlimited thereto.

The CBL 154 prevents current from being concentrated on the shortestpath between the first and second electrodes 160 and 170, so that thelight emission efficiency of the light emitting device 100 can beimproved.

The light emitting structure 145 may be formed on both of the ohmiccontact layer 156 and the protection layer 155.

The light emitting structure 145 may include a plurality of compoundsemiconductor materials of group III to V elements.

The light emitting structure 145 may include a first conductivesemiconductor layer 150, an active layer 140 on the first conductivesemiconductor layer 150, and a second conductive semiconductor layer 130on the active layer.

The first conductive semiconductor layer 150 may be formed on a part ofthe protection layer 155, the ohmic contact layer 156, and the CBL 154.The first conductive semiconductor layer 150 may include a P typesemiconductor layer including P type dopants. The P type semiconductorlayer may include a compound semiconductor material of group III to Velements. For example, the P type semiconductor layer may include oneselected from the group consisting of GaN, AlN, AlGaN, InGaN, InN,InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP and AlGaInP. The P type dopantmay include Mg, Zn, Ga, Sr, or Ba. The first conductive semiconductorlayer 150 may have a single layer structure or a multiple layerstructure, but the embodiment is not limited thereto.

The first conductive semiconductor layer 150 supplies a plurality ofcarriers to the active layer 140.

The active layer 140 is formed on the first conductive semiconductorlayer 150, and may include one of a single quantum well structure, amultiple quantum well (MQW) structure, a quantum wire structure or aquantum dot structure, but the embodiment is not limited thereto.

If the active layer 140 has a quantum well structure, the active layer140 may have a single quantum well structure having a well layer havinga compositional formula of InxAlyGa1-yN (0≦x≦1, 0≦y≦1, 0≦x+y≦1), and abarrier layer having a compositional formula of InaAlbGa1-a-bN (0≦a≦1,0≦b≦1, 0≦a+b≦1). The well layer may include a material having energybandgap lower than that of the barrier layer.

The active layer 140 may have the stack structure of a well layer and abarrier layer including compound semiconductor materials of group III toV elements. The compound semiconductor materials constituting the activelayer 140 may include GaN, InGaN, or AlGaN. Therefore, the active layer140 may include the stack structure of InGaN well/GaN barrier layers,InGaN well/AlGaN barrier layers, or InGaN well/InGaN barrier layers, butthe embodiment is not limited thereto.

The active layer 140 may generate light having a wavelengthcorresponding to the bandgap determined according to the semiconductormaterial of the active layer 140 through the recombination of theelectrons and the holes provided from the first and second conductivesemiconductor layers 112 and 116.

Although not shown, a conductive clad layer may be formed on and/orunder the active layer 140. The clad layer may include an AlGaN-basedsemiconductor. For example, a P type clad layer doped with P typedopants is disposed between the first conductive semiconductor layer 150and the active layer 140, and an N type clad layer doped with N typedopants may be disposed between the active layer 140 and the secondconductive semiconductor layer 130.

The conductive clad layer prevents plural holes and electrodes suppliedto the active layer 140 from transferring to the first and secondconductive semiconductor layers 150 and 130. Accordingly, a greateramount of holes and electrons supplied to the active layer 140 arerecombined with each other due to the conductive clad layer, so that thelight emission efficiency of the light emitting device 100 can beimproved.

The second conductive semiconductor layer 130 may be formed on theactive layer 140. The second conductive semiconductor layer 130 mayinclude an N type semiconductor layer including N type dopants. Thesecond conductive semiconductor layer 130 may include compoundsemiconductor materials of group III to V elements. For example, thesecond conductive semiconductor layer 130 may include one selected fromthe group consisting of GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN,AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. The N type dopant may include Si,Ge, Sn, Se, or Te. The second conductive semiconductor layer 130 mayhave a single layer structure or a multiple layer structure, but theembodiment is not limited thereto.

A roughness structure 132 may be formed on the top surface of the secondconductive semiconductor layer 130 to improve light extractionefficiency. The roughness structure 132 may be a random pattern formedthrough a wet etching process or a periodical pattern such as a photoniccrystal structure formed through a patterning process, but theembodiment is not limited thereto.

The roughness structure 132 may periodically have concave and convexshapes. The concave and convex shapes may have a rounded surface or twoopposite inclined surfaces convergent at a vertex

For example, the roughness structure 132 may have a photonic crystalstructure to selectively transmit or reflect light having a specificwavelength band. The roughness structure 132 may have a period of about50 nm to about 3000 nm, but the embodiment is not limited thereto.

Meanwhile, a semiconductor layer having a polarity opposite to that ofthe first conductive semiconductor layer 150 may be formed under thefirst conductive semiconductor layer 150. The first conductivesemiconductor layer 150 may include a P type semiconductor layer, andthe second conductive semiconductor layer 130 may include an N typesemiconductor layer. In contrast, the first conductive semiconductorlayer 150 may include an N type semiconductor layer, and the secondconductive semiconductor layer 130 may include a P type semiconductorlayer. Accordingly, the light emitting structure 145 may have at leastone of an N-P junction structure, a P-N junction structure, an N-P-Njunction structure, and a P-N-P junction structure.

The nano-tube layer 135 including CNTs (Carbon Nano Tubes) may be formedon the top surface of the second conductive semiconductor layer 130 ofthe light emitting structure 145.

The carbon nano tube is a nano-size carbon structure having the shape ofa tube formed by linking hexagons consisting of six carbons with eachother. The carbon nano tube represents high electrical conductivity andthermal conductivity, and has a transparent optical property. The carbonnano tube may be formed through at least one of an Arc-discharge scheme,a laser vaporization scheme, a plasma enhanced chemical vapor depositionscheme, a thermal chemical vapor deposition scheme, a vapor phase growthscheme, an electrolysis scheme, and a flame synthetic scheme, but theembodiment is not limited thereto.

The nano-tube layer 135 may be formed by coating a plurality of carbonnano tubes on the light emitting structure 145, or may be prepared inthe form of a film and attached to the light emitting structure 145.

For example, the nano-tube layer 135 may be a thin film having athickness in the range of about 10 nm to about 10 μm. The nano-tubelayer 135 may have a pattern according to the shape of the roughnessstructure 132 formed on the top surface of the second conductivesemiconductor layer 130.

Since the nano-tube layer 135 is formed on the top surface of the lightemitting structure 145 and has high electrical conductive, the nano-tubelayer 135 uniformly spreads current to the light emitting structure 145,so that current can be prevented from being concentrated on the secondelectrode 170 and the peripheral portion of the second electrode 170.Accordingly, the light extraction efficiency of the light emittingdevice 100 can be improved. To maximize the spreading of current,preferably, the nano-tube layer 135 has to be formed at an areacorresponding to at least 70% of a area of a top surface of the lightemitting structure 145 or must have a predetermined pattern, but theembodiment is not limited thereto.

Since the nano-tube layer 135 has high thermal conductivity, heatemitted from the light emitting structure 145 may be effectivelydissipated to the outside.

Although the nano-tube layer 135 is transparent optically, since therefractive index of the nano-tube layer 135 may be less than that of thelight emitting structure 145, the light extraction efficiency can beimproved due to the refractive index difference

Since the nano-tube layer 135 allows current to be smoothly supplied toboth of a semiconductor and metal, the nano-tube layer 135 may reducethe contact resistance between the second electrode 170 and the secondconductive layer 130.

The passivation layer 180 may be formed on at least a lateral surface ofthe light emitting structure 145. In detail, one end of the passivationlayer 180 is formed at an outer peripheral portion of a top surface ofthe second conductive semiconductor layer 130, and an opposite end ofthe passivation layer 180 may extend to a top surface of the protectionlayer 155 by passing or crossing through the lateral surface of thelight emitting structure 145, but the embodiment is not limited thereto.In other words, the passivation layer 180 may extend from the topsurface of the protection layer 155 to the outer peripheral portion ofthe top surface of the second conductive semiconductor layer 130 throughthe lateral surfaces of the first conductive semiconductor layer 150,the active layer 140, and the second conductive semiconductor layer 130.

The passivation layer 180 may prevent the light emitting structure 145from being electrically shorted with a conductive member such as anexternal electrode. For example, the passivation layer 180 may includean insulating material including SiO2, SiOx, SiOxNy, Si3N4, TiO2, orAl2O3, but the embodiment is not limited thereto.

The second electrode 170 may be formed on the nano-tube layer 135.

The second electrode 170 may have a single layer structure or a multiplelayer structure including at least one selected from the groupconsisting of Au, Ti, Ni, Cu, Al, Cr, Ag and Pt.

Hereinafter, the method of manufacturing the light emitting deviceaccording to the first embodiment will be described in detail.

FIGS. 2 to 11 are views showing the manufacturing process of the lightemitting device according to the first embodiment.

Referring to FIG. 2, the light emitting structure 145 may be formed on agrowth substrate 110.

For example, the growth substrate 110 may include at least one selectedfrom the group consisting of sapphire (Al2O3), SiC, GaAs, GaN, ZnO, Si,GaP, InP and Ge, but the embodiment is not limited thereto.

The second conductive semiconductor layer 130, the active layer 140, andthe first conductive semiconductor layer 150 are sequentially grown fromthe growth substrate 110, thereby forming the light emitting structure145.

For example, the light emitting structure 145 may be formed through oneof an MOCVD (Metal Organic Chemical Vapor Deposition) scheme, a CVD(Chemical Vapor Deposition) scheme, a PECVD (Plasma-Enhanced ChemicalVapor Deposition) scheme, an MBE (Molecular Beam Epitaxy) scheme, and anHYPE (Hydride Vapor Phase Epitaxy) scheme, but the embodiment is notlimited thereto.

Meanwhile, a buffer layer (not shown) or an undoped semiconductor layer(not shown) may be additionally formed between the light emittingstructure 145 and the growth substrate 110 to reduce lattice constantmismatch between the light emitting structure 145 and the growthsubstrate 110.

The buffer layer may include one selected from the group consisting ofInAlGaN, GaN, AlGaN, InGaN, AlInN, AlN, and InN, but the embodiment isnot limited thereto.

Referring to FIG. 3, the protection layer 155 and the CBL 154 may beformed on the top surface of the light emitting structure 145.

The protection layer 155 may be formed at a chip boundary region, thatis, a boundary region between first and second chips T1 and T2 on thefirst conductive semiconductor layer 150. Thereafter, the first andsecond chip regions T1 and T2 may be subject to a scribing process sothat the first and second chip regions T1 and T2 are separated from eachother, thereby manufacturing a unit light emitting device. Accordingly,each chip region T1 or T2 may be defined as a region for the acquisitionof a unit light emitting device.

The protection layer 155 may be formed in the vicinity of a boundaryregion between the first and second chip regions T1 and T2 by using amask pattern. Since FIG. 3 is a 2-D sectional view, FIG. 3 shows thatthe protection layer 155 is formed in the vicinity of only the boundaryregion between the first and second chip regions T1 and T2. However,actually, the protection layer 155 may be formed in the vicinity of allboundary regions between one chip region and all chip regions adjacentto the chip region. When viewed in a plan view, the protection layer 155may have a ring shape, a loop shape, or a frame shape. The protectionlayer 155 may be formed through various deposition schemes such as asputtering scheme, an E-beam deposition scheme, and a PECVD (PlasmaEnhanced Chemical Vapor Deposition) scheme.

The protection layer 155 prevents the light emitting structure 145 frombeing electrically shorted with the first electrode 160, or enhances theadhesive strength between the light emitting structure 145 and thereflective layer 570, so that the reliability for the light emittingdevice 100 can be improved.

The CBL 154 may be formed on the first conductive semiconductor layer150, at least a part of which perpendicularly overlaps with the secondelectrode 170 to be formed in the post process.

The CBL 154 and the protection layer 155 may include the same materialand may be simultaneously formed through the same process, or mayinclude different materials and may be formed separately from eachother.

The CBL 154 may have a thickness thinner than that of the protectionlayer 155. In other words, a top surface of the protection layer 155 maybe higher than the top surface of the CBL 154.

The CBL 154 and the protection layer 155 may be formed through adeposition scheme or a plating scheme.

The protection layer 155 and the CBL 154 may have an electricalinsulating property or may include a material making schottky contactwith respect to the first conductive semiconductor layer 150. In otherwords, the protection layer 155 and the CBL 154 may include at least oneselected from the group consisting of ITO, IZO, IZTO, IAZO, IGZO, IGTO,AZO, ATO, ZnO, SiO2, SiOx, SiOxNy, Si3N4, Al2O3, TiOx, Ti, Al, and Cr.

Referring to FIG. 4, the ohmic contact layer 156 is formed on the firstconductive semiconductor layer 150 and the CBL 154, and the reflectivelayer 157 may be formed on the ohmic contact layer 156 and theprotection layer 155.

The CBL 154 is configured to fill the ohmic contact layer 156.

The ohmic contact layer 156 and the reflective layer 157 may be formedone of an E-beam deposition scheme, a sputtering scheme, and a PECVD(Plasma Enhanced Chemical Vapor Deposition) scheme.

Referring to FIG. 5, the adhesive layer 158 may be formed on thereflective layer 157, and the first electrode 160 may be formed on theadhesive layer 158.

The first electrode 160 may be firmly bonded by the adhesive layer 158.Meanwhile, if the first electrode 160 is formed through a depositionscheme or a plating scheme, the adhesive layer 158 may be not formed.

Referring to FIG. 6, after turning the substrate 110 at 180 degrees, thegrowth substrate 110 may be removed.

The growth substrate 110 may be removed through at least one of an LLO(Laser Lift Off) scheme, a CLO (Chemical Lift Off) scheme, and aphysical grinding scheme.

The LLO process is to irradiate a laser beam to the interface betweenthe growth substrate 110 and the second conductive semiconductor layer130, so that the substrate 110 can be separated from the secondconductive semiconductor layer 130.

The chemical etching process includes a wet etching process to removethe substrate 110 such that the second conductive semiconductor layer130 is exposed.

The growth substrate 110 is sequentially ground from a top surface byusing a physical grinder so that the second conductive semiconductorlayer 130 is exposed.

A cleaning process may be additionally performed to remove residues ofthe substrate 110 remaining on the top surface of the second conductivesemiconductor layer 130 after removing the substrate 110. The cleaningprocess may include plasma treatment or an asking process using oxygenor nitrogen.

As the growth substrate 110 is removed, the top surface of the secondconductive semiconductor layer 130 can be exposed.

Referring to FIG. 7, an isolation etching process is performed along theboundary region between the first and second chip regions T1 and T2 toseparate a unit chip region including the light emitting structure 145.The protection layer 155 of a boundary region 105 between the first andsecond chip regions T1 and T2 may be exposed through the isolationetching process.

The lateral surface of the light emitting structure 145 may be inclinedthrough the isolating etching process.

Simultaneously, the roughness structure 132 may be formed on the topsurface of the light emitting structure 145, that is, the top surface ofthe second conductive semiconductor layer 130.

The isolating etching process may include a dry etching process such asICP (Inductively Coupled Plasma).

The roughness structure 132 may have a random pattern through a wetetching process, or may have a photonic crystal structure according to amask pattern, but the embodiment is not limited thereto.

Referring to FIG. 8, the passivation layer 180 may be formed on at leasta lateral surface of the light emitting structure 145, and on theprotection layer 155 between the first and second chip regions T1 andT2. In other words, the passivation layer 180 contacts a top surface ofthe protection layer of the boundary region 105 between the first andsecond chip regions T1 and T2. The passivation layer 180 may extend toan outer peripheral portion of the top surface of the second conductivesemiconductor layer 130 by passing or crossing through the firstconductive semiconductor layer 150, the active layer 140, and the secondconductive semiconductor layer 130.

The passivation layer 180 prevents the light emitting structure 145 frombeing electrically shorted with a conductive support member such as anexternal electrode. The passivation layer 180 may include an insulatingmaterial including SiO2, SiOx, SiOxNy, Si3N4, TiO2, or Al2O3, but theembodiment is not limited thereto.

The passivation layer 180 may be formed through various depositionprocesses such as an E-beam deposition scheme, and a PECVD scheme or asputtering scheme.

The roughness structure 132 may be formed on the top surface of thesecond conductive semiconductor layer 130 by using the passivation layer180 as a mask after the passivation layer 180 has been formed.

In other words, the roughness structure 132 may be formed before thepassivation layer 180 is formed, or after the passivation layer 180 hasbeen formed.

Referring to FIG. 9, the nano-tube layer 135 may be formed on the topsurface of the light emitting structure 145, that is, the secondconductive semiconductor layer 130.

The nano-tube layer 135 may be formed through a coating scheme such as aspin coating scheme or a dip coating scheme, or may be prepared in theform of a film and attached to the light emitting structure 145.However, the embodiment is not limited thereto.

The nano-tube layer 135 may be selectively formed on the top surface ofthe second conductive semiconductor layer 130. For example, thenano-tube layer 135 may be formed on the whole region of the secondconductive semiconductor layer 130 or on a region having an areacorresponding to at least 70% of an area of the second conductivesemiconductor layer 130.

Referring to FIG. 10, the second electrode 170 may be formed on thenano-tube layer 135. The second electrode 170 may be plated ordeposited.

Referring to FIG. 11, a chip separation process is performed to cut theboundary region between the first and second chip regions T1 and T2,thereby dividing a plurality of chips into the unit of an individualchip. Accordingly, the light emitting device 100 according to theembodiment can be manufactured.

The chip separation process may include a breaking process to dividechips by apply physical force using a blade, a laser scribing process todivide chips by irradiating a laser beam into a chip boundary region,and an etching process including a wet etching process or a dry etchingprocess, but the embodiment is not limited thereto.

FIG. 12 is a side sectional view showing a light emitting device 100Aaccording to a second embodiment.

The light emitting device 100A according to the second embodiment hasthe same structure as that of the first embodiment except for the shapeof the nano-tube layer. Accordingly, the same reference numbers will beassigned to elements of the second embodiment identical to those of thefirst embodiment, and the details thereof will be omitted.

Referring to FIG. 12, the light emitting device 100 according to thesecond embodiment includes the first electrode 160, the adhesive layer158 on the first electrode 160, the reflective layer 157 on the adhesivelayer 158, the protection layer 155 on an outer peripheral portion ofthe top surface of the reflective layer 157, the ohmic contact layer 156on the reflective layer 157, the light emitting structure 145 formed onthe ohmic contact layer 156 and the protection layer 155 to generatelight, a nano-tube layer 135 a selectively formed on the top surface ofthe light emitting structure 145, the passivation layer 180 on a lateralsurface of the light emitting structure 145, and a second electrode 170a on the light emitting structure 145.

The second electrode 170 a may directly contacts the top surface of thelight emitting structure 145, that is, the top surface of the secondconductive semiconductor layer 130.

To this end, after the nano-tube layer 135 a corresponding to the regionfor the second electrode 170 a is selectively removed, the secondelectrode 170 a is formed at the removed region of the nano-tube layer135 a such that the second electrode 170 a directly contacts the secondconductive semiconductor layer 130.

After the second electrode 170 a has been formed on the secondconductive semiconductor layer 130, the nano-tube layer 135 a may beformed by using a mask on the second conductive semiconductor layer 130around the second electrode 170 a, but the embodiment is not limitedthereto. In other words, the second electrode 170 a is surrounded by thenano-tube layer 135 a.

FIG. 13 is a side sectional view showing a light emitting device 100Baccording to a third embodiment.

The light emitting device 100B according to the third embodiment has thesame structure as that of the first embodiment except for the shape ofthe nano-tube layer. Accordingly, the same reference numbers will beassigned to elements of the third embodiment identical to those of thefirst embodiment, and the details thereof will be omitted.

Referring to FIG. 13, the light emitting device 100B according to thethird embodiment includes the first electrode 160, the adhesive layer158 on the first electrode 160, the reflective layer 157 on the adhesivelayer 158, the protection layer 155 on an outer peripheral portion ofthe top surface of the reflective layer 157, the ohmic contact layer 156on the reflective layer 157, the light emitting structure 145 formed onthe ohmic contact layer 156 and the protection layer 155 to generatelight, a nano-tube layer 135 b selectively formed on the top surface ofthe light emitting structure 145, the passivation layer 180 on thelateral surface of the light emitting structure 145, and the secondelectrode 170 on the nano-tube layer 135 b.

The nano-tube layer 135 b may be formed at a region between the secondelectrode 170 and the second conductive semiconductor layer 130 in orderto reduce the contact resistance between the second electrode 170 andthe second conductive semiconductor layer 130. In other words, thenano-tube layer 135 b may have the same area as that of the secondelectrode 170.

To this end, after patterning the nano-tube layer 135 b, the secondelectrode 170 may be formed only on the nano-tube layer 135 b.

After the nano-tube layer 135 b and the second electrode 170 aresubsequently formed, the second electrode 170 and the nano-tube layer135 b are sequentially and selectively removed, so that the secondelectrode 170 and the nano-tube layer 135 b having the same size and thesame pattern may be formed.

FIG. 14 is a side sectional view showing a light emitting device 100Caccording to a fourth embodiment.

The light emitting device 100C according to the fourth embodiment hasthe same structure as that of the first embodiment except that a secondelectrode 170 b is formed on the second conductive semiconductor layer130 and a nano-tube layer 135 c. Accordingly, the same reference numberswill be assigned to elements of the fourth identical to those of thefirst embodiment, and the details thereof will be omitted.

Referring to FIG. 14, in the light emitting device 100C according to thefourth embodiment, a bottom surface of the second electrode 170 b maycontact both of the second conductive semiconductor layer 130 and thenano-tube layer 135 c.

To this end, a part of the nano-tube layer 135 c may be removed toexpose the second conductive semiconductor layer 130. The secondelectrode 170 b passes through the nano-tube layer 135 c such that thesecond electrode 170 b overlaps with a part of the nano-tube layer 135c.

The second electrode 170 b contacts the second conductive semiconductorlayer 130, and passes through the nano-tube layer 135 c to extend fromthe second conductive semiconductor layer 130 to a top surface of thenano-tube layer 135 c. In addition, the second electrode 170 b may beformed at a part of the nano-tube layer 135 c to overlap with a part ofthe nano-tube layer 135 c.

FIG. 15 is a side sectional view showing a light emitting device 200according to a fifth embodiment.

Referring to FIG. 15, the light emitting device 200 according to thefifth embodiment includes a growth substrate 210, a light emittingstructure 220 including a first conductive semiconductor layer 212, anactive layer 214, and a second conductive semiconductor layer 216 on thegrowth substrate 210, a first electrode 230 on the first conductivesemiconductor layer 212, a transparent electrode 250 on the secondconductive semiconductor layer 216, a second electrode 260 with a firstportion 260-1 on the current blocking layer 240 and with a secondportion 260-2 of wider lateral extent than the first portion andcontacting the nano tube layer 250, and a passivation layer 270 at anouter peripheral portion of at least the light emitting structure 220.

The growth substrate 210 may include at least one of sapphire (Al2O3),SiC, Si, GaAs, GaN, ZnO, Si, GaP, InP, and Ge.

The light emitting structure 220 may include compound semiconductormaterials of group III to V elements.

The first conductive semiconductor layer 212 may include an N typesemiconductor layer doped with an N type dopant, and the secondconductive semiconductor layer 216 may include a P type semiconductorlayer doped with a P type dopant, but the embodiment is not limitedthereto.

The nano tube layer 250 may be formed on the second conductivesemiconductor layer 216.

The nano tube layer 250 spreads current supplied from the secondelectrode 260 such that the current can be supplied to the whole regionof the second conductive semiconductor layer 216.

The second electrode 260 may extends from the second conductivesemiconductor layer 216 while passing through the nano tube layer 250.

In this case, the quantity of current supplied to the second conductivesemiconductor layer 216 directly contacting the second electrode 260 isgreater than the quantity of current supplied to the second conductivesemiconductor layer 216 through the nano tube layer 250. Accordingly,light is uniformly emitted from the whole region of the active layer214.

Accordingly, a CBL 240 may be formed on the second conductivesemiconductor layer 216 directly contacting the second electrode 260.The CBL 240 has a size greater than the areas of at least two secondelectrodes 160. The current supplied from the second electrode 260 maybe supplied at the minimum of quantity through to the CBL 140 or may notbe supplied at all due to the CBL 240. In contrast, after the currentsupplied from the second electrode 260 has been spread through thetransparent electrode 250, the current may be uniformly supplied to thesecond conductive semiconductor layer 216. Accordingly, the uniformlight is emitted from the active layer 214 so that the light emissionefficiency of the light emitting device 200 can be improved.

The passivation layer 270 may be formed at an outer peripheral portionof the light emitting structure 220 except for the first and secondelectrodes 230 and 260. For example, the passivation layer 270 may beformed on an outer peripheral portion of the lateral surface of thefirst conductive semiconductor layer 212, an outer peripheral portion ofthe lateral surface of the active layer 214, an outer peripheral portionof the second conductive semiconductor layer 215 and the top surface ofthe second conductive semiconductor layer 215.

The passivation layer 270 may include an insulating material includingSiO2, SiOx, SiOxNy, Si3N4, TiO2, or Al2O3, but the embodiment is notlimited thereto.

Although not shown, the transparent electrode 250 is not formed in athrough hole formed by the second electrode 260, but may be formed onthe CBL in such a manner that the transparent electrode 250 covers atleast the whole region of the CBL. In other words, after forming thenano tube layer to cover the whole region of the CBL, the secondelectrode may be formed on the transparent electrode corresponding tothe CBL. The CBL may be formed between the transparent electrodecorresponding to the second electrode and the second semiconductorlayer. Accordingly, the second electrode does not contact the CBL.

Although not shown, a roughness structure may be formed on the secondconductive semiconductor layer 216, and thereby on the light emittingstructure 220.

FIG. 16 is a light emitting device package 30 including the lightemitting device according to the embodiment.

Referring to FIG. 16, the light emitting device package 30 includes abody 20, first and second electrode layers 31 and 32 installed in thebody 20, the light emitting device 100 provided on the body 20 andelectrically connected to the first and second electrode layers 31 and32, and a molding member 40 that surrounds the light emitting device 100on the body 20.

The body 20 may include silicon, synthetic resin or metallic material.When viewed from the top, the body 20 has a cavity having an open upperportion and formed with an inclined inner wall.

The first and second electrode layers 31 and 32 are electricallyisolated from each other and pass through the body 20. In detail, oneends of the first and second electrode layers 31 and 32 are disposed inthe cavity 50 and the other ends of the first and second electrodelayers 31 and 32 are attached to an outer surface of the body 20 andexposed to the outside.

The first and second electrode layers 31 and 32 supply power to thelight emitting device 100 and improve the light efficiency by reflectingthe light emitted from the light emitting device 100. Further, the firstand second electrode layers 31 and 32 dissipate heat generated from thelight emitting device 100 to the outside.

The light emitting device 100 can be installed on the body 20 or thefirst or second electrode layer 31 or 32.

The wire 60 of the light emitting device 100 may be electricallyconnected to one of the first and second electrode layers 31 and 32, butthe embodiment is not limited thereto. In this case, the electrode layerthat is not connected to the wire 60 may be electrically connected tothe rear surface of the light emitting device 100.

The molding member 40 surrounds the light emitting device 100 to protectthe light emitting device 100. In addition, the molding member 40 mayinclude luminescence material to change the wavelength of the lightemitted from the light emitting device 100 by the luminescence material.

The light emitting device or the light emitting device package accordingto the embodiment may be applied to the light unit. The light unit hasan array structure of a plurality of light emitting devices or aplurality of light emitting device packages. The light unit may includethe display device as shown in FIGS. 17 and 18 and the lighting deviceas shown in FIG. 19. In addition, the light unit may include a lightinglamp, a signal lamp, a headlight of a vehicle, and an electricsignboard.

FIG. 17 is an exploded perspective view showing the display apparatusaccording to the embodiment.

Referring to FIG. 17, the display device 1000 includes a light guideplate 1041, a light emitting module 1031 for supplying the light to thelight guide plate 1041, a reflective member 1022 provided below thelight guide plate 1041, an optical sheet 1051 provided above the lightguide plate 1041, a display panel 1061 provided above the optical sheet1051, and a bottom cover 1011 for receiving the light guide plate 1041,the light emitting module 1031, and the reflective member 1022. However,the embodiment is not limited to the above structure.

The bottom cover 1011, the reflective sheet 1022, the light guide plate1041 and the optical sheet 1051 may constitute a light unit 1050.

The light guide plate 1041 diffuses the light supplied from the lightemitting module 1031 to provide surface light. The light guide plate1041 may include transparent material. For instance, the light guideplate 1041 may include one of acryl-based resin, such as PMMA(polymethyl methacrylate, PET (polyethylene terephthalate), PC(polycarbonate), COC (cyclic olefin copolymer) and PEN (polyethylenenaphthalate) resin.

The light emitting module 1031 is disposed at one side of the lightguide plate 1041 to supply the light to at least one side of the lightguide plate 1041. The light emitting module 1031 serves as the lightsource of the display device.

At least one light emitting module 1031 is provided to directly orindirectly supply the light from one side of the light guide plate 1041.The light emitting module 1031 may include a substrate 1033 and lightemitting device packages 30 according to the embodiments. The lightemitting device packages 30 are arranged on the substrate 1033 whilebeing spaced apart from each other at the predetermined interval. Thesubstrate 1033 may include a printed circuit board (PCB), but theembodiment is not limited thereto. In addition, the substrate 1033 mayalso include a metal core PCB (MCPCB) or a flexible PCB (FPCB), but theembodiment is not limited thereto. If the light emitting device packages30 are installed on the side of the bottom cover 1011 or on a heatdissipation plate, the substrate 1033 may be omitted. The heatdissipation plate partially contacts the top surface of the bottom cover1011. Thus, the heat generated from the light emitting device packages30 can be emitted to the bottom cover 1011 through the heat dissipationplate.

In addition, the light emitting device packages 30 are arranged suchthat light exit surfaces of the light emitting device packages 30 arespaced apart from the light guide plate 1041 by a predetermineddistance, but the embodiment is not limited thereto. The light emittingdevice packages 30 may directly or indirectly supply the light to alight incident surface, which is one side of the light guide plate 1041,but the embodiment is not limited thereto.

The reflective member 1022 is disposed below the light guide plate 1041.The reflective member 1022 reflects the light, which travels downwardthrough the bottom surface of the light guide plate 1041, toward thedisplay panel 1061, thereby improving the brightness of the displaypanel 1061. For instance, the reflective member 1022 may include PET, PCor PVC resin, but the embodiment is not limited thereto. The reflectivemember 1022 may serve as the top surface of the bottom cover 1011, butthe embodiment is not limited thereto.

The bottom cover 1011 may receive the light guide plate 1041, the lightemitting module 1031, and the reflective member 1022 therein. To thisend, the bottom cover 1011 has a receiving section 1012 having a boxshape with an opened top surface, but the embodiment is not limitedthereto. The bottom cover 1011 can be coupled with the top cover (notshown), but the embodiment is not limited thereto.

The bottom cover 1011 can be manufactured through a press process or anextrusion process by using metallic material or resin material. Inaddition, the bottom cover 1011 may include metal or non-metallicmaterial having superior thermal conductivity, but the embodiment is notlimited thereto.

The display panel 1061, for instance, is an LCD panel including firstand second transparent substrates, which are opposite to each other, anda liquid crystal layer disposed between the first and second substrates.A polarizing plate can be attached to at least one surface of thedisplay panel 1061, but the embodiment is not limited thereto. Thedisplay panel 1061 displays information by blocking the light generatedfrom the light emitting module 1031 or allowing the light to passtherethrough. The display device 1000 can be applied to various portableterminals, monitors of notebook computers, monitors or laptop computers,and televisions.

The optical sheet 1051 is disposed between the display panel 1061 andthe light guide plate 1041 and includes at least one transmittive sheet.For instance, the optical sheet 1051 includes at least one of adiffusion sheet, a horizontal and vertical prism sheet, and a brightnessenhanced sheet. The diffusion sheet diffuses the incident light, thehorizontal and vertical prism sheet concentrates the incident light ontothe display panel 1061, and the brightness enhanced sheet improves thebrightness by reusing the lost light. In addition, a protective sheetcan be provided on the display panel 1061, but the embodiment is notlimited thereto.

The light guide plate 1041 and the optical sheet 1051 can be provided inthe light path of the light emitting module 1031 as optical members, butthe embodiment is not limited thereto.

FIG. 18 is a sectional view showing a display apparatus according to theembodiment.

Referring to FIG. 18, the display device 1100 includes a bottom cover1152, a substrate 1120 on which the light emitting device packages 30are arranged, an optical member 1154, and a display panel 1155.

The substrate 1120 and the light emitting device packages 30 mayconstitute the light emitting module 1060. In addition, the bottom cover1152, at least one light emitting module 1060, and the optical member1154 may constitute the light unit (not shown).

The bottom cover 1151 can be provided with a receiving section 1153, butthe embodiment is not limited thereto.

The optical member 1154 may include at least one of a lens, a lightguide plate, a diffusion sheet, a horizontal and vertical prism sheet,and a brightness enhanced sheet. The light guide plate may include PC orPMMA (Poly methyl methacrylate). The light guide plate can be omitted.The diffusion sheet diffuses the incident light, the horizontal andvertical prism sheet concentrates the incident light onto the displaypanel 1155, and the brightness enhanced sheet improves the brightness byreusing the lost light.

The optical member 1154 is disposed above the light emitting module 1060in order to convert the light emitted from the light emitting module1060 into the surface light. In addition, the optical member 1154 maydiffuse or collect the light.

FIG. 19 is a perspective view showing a lighting apparatus according tothe embodiment.

Referring to FIG. 19, the lighting device 1500 includes a case 1510, alight emitting module 1530 installed in the case 1510, and a connectionterminal 1520 installed in the case 1510 to receive power from anexternal power source.

Preferably, the case 1510 includes material having superior heatdissipation property. For instance, the case 1510 includes metallicmaterial or resin material.

The light emitting module 1530 may include a substrate 1532 and lightemitting device packages 30 installed on the substrate 1532. The lightemitting device packages 30 are spaced apart from each other or arrangedin the form of a matrix.

The substrate 1532 includes an insulating member printed with a circuitpattern. For instance, the substrate 1532 includes a PCB, an MCPCB, anFPCB, a ceramic PCB, and an FR-4 substrate.

In addition, the substrate 1532 may include material that effectivelyreflects the light. A coating layer can be formed on the surface of thesubstrate 1532. At this time, the coating layer has a white color or asilver color to effectively reflect the light.

At least one light emitting device package 30 is installed on thesubstrate 1532. Each light emitting device package 30 may include atleast one LED (light emitting diode) chip. The LED chip may include anLED that emits the light of visible ray band having red, green, blue orwhite color and a UV (ultraviolet) LED that emits UV light.

The light emitting device packages 30 of the light emitting module 1530can be variously arranged to provide various colors and brightness. Forinstance, the white LED, the red LED and the green LED can be arrangedto achieve the high color rendering index (CRI).

The connection terminal 1520 is electrically connected to the lightemitting module 1530 to supply power to the light emitting module 1530.The connection terminal 1520 has a shape of a socket screw-coupled withthe external power source, but the embodiment is not limited thereto.For instance, the connection terminal 1520 can be prepared in the formof a pin inserted into the external power source or connected to theexternal power source through a wire.

According to the embodiment, the method of manufacturing the lightemitting device includes the steps of preparing a first electrodeincluding a conductive support member, forming a light emittingstructure including a first semiconductor layer, an active, and a secondsemiconductor layer on the first electrode, forming a nano-tube layerincluding a plurality of carbon nano tubes on the light emittingstructure; and forming a second electrode on the light emittingstructure.

According to the embodiment, the nano tube layer is formed on the lightemitting structure to uniformly spread current, thereby preventingcurrent from being centralized. Accordingly, the light emissionefficiency of the light emitting device can be improved.

According to the embodiment, the nano-tube layer is formed on the lightemitting structure, so that heat emitted from the light emittingstructure can be rapidly dissipated through the nano-tube layer.

According to the embodiment, a nano-tube layer having a refractive indexless than that of the light emitting structure is formed, so that thelight extraction efficiency of the light emitting device can be improveddue to the refractive index difference between the light emittingstructure and the nano-tube layer.

According to the embodiment, a nano-tube layer is formed between thelight emitting structure and the electrode so that the contactresistance between the light emitting structure and the electrode can bereduced. Accordingly, current supplied to the electrode can moresmoothly flow to the light emitting structure.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A light emitting device comprising: a lightemitting structure including a first semiconductor layer, an activelayer, and a second semiconductor layer; a nano-tube layer includingcarbon nano tubes on the second semiconductor layer; a current blockinglayer between the second semiconductor layer and the nano-tube layer; afirst electrode electrically connected to the first semiconductor layer;and a second electrode electrically connected to the secondsemiconductor layer, wherein the second electrode includes a firstportion on the current blocking layer, and a second portion on the firstportion, wherein the first portion of the second electrode contacts thecurrent blocking layer, and wherein the second portion of the secondelectrode contacts the nano-tube layer.
 2. The light emitting device ofclaim 1, wherein a part of the second electrode is disposed on a part ofthe nano-tube layer.
 3. The light emitting device of claim 2, whereinthe part of the nano-tube layer is disposed between the part of thesecond electrode and the second semiconductor layer.
 4. A light emittingdevice comprising: a light emitting structure including a firstsemiconductor layer, an active layer, and a second semiconductor layer;a nano-tube layer including carbon nano tubes on the secondsemiconductor layer; a current blocking layer between the secondsemiconductor layer and the nano-tube layer; a first electrodeelectrically connected to the first semiconductor layer; and a secondelectrode electrically connected to the second semiconductor layer,wherein the nano-tube layer has a refractive index lower than arefractive index of the light emitting structure, wherein the secondelectrode includes a first portion on the current blocking layer, and asecond portion on the first portion, wherein a top surface of thecurrent blocking layer is higher than a bottom surface of the nano-tubelayer.
 5. The light emitting device of claim 1, further comprising aconcavo-convex structure on the light emitting structure.
 6. The lightemitting device of claim 1, further comprising a passivation layer on atleast a lateral surface of the light emitting structure.
 7. A lightemitting device comprising: a substrate; a light emitting structure onthe substrate and including a first semiconductor layer, an active layeron the first semiconductor layer, and a second semiconductor layer onthe active layer; a first electrode electrically connected to the firstsemiconductor layer; a nano-tube layer on the second semiconductorlayer; a current blocking layer between the second semiconductor layerand the nano-tube layer; and a second electrode on the nano-tube layer,wherein a portion of the nano-tube layer is disposed between the currentblocking layer and the second electrode, wherein the portion of thenano-tube layer disposed between the current blocking layer and thesecond electrode contacts a top surface of the current blocking layer,and wherein the second electrode contacts a portion of the currentblocking layer and the portion of the nano-tube layer.
 8. The lightemitting device of claim 7, wherein the nano-tube layer includes athrough-hole, and wherein a portion of the second electrode is disposedin the through-hole, wherein the second electrode includes a firstportion on the portion of the current blocking layer, and a secondportion on the first portion of the second electrode.
 9. The lightemitting device of claim 8, wherein the current blocking layer isdisposed in the through-hole, and wherein a lateral width of the secondportion of the second electrode is greater than a lateral width of thefirst portion of the second electrode.
 10. The light emitting device ofclaim 7, wherein the top surface of the current blocking layer is higherthan a bottom surface of the nano-tube layer.
 11. The light emittingdevice of claim 1, wherein a lateral width of the second portion isgreater than a lateral width of the first portion.
 12. The lightemitting device of claim 1, wherein a top surface of the currentblocking layer is higher than a bottom surface of the nano-tube layer.13. The light emitting device of claim 4, wherein a lateral width of thesecond portion is greater than a lateral width of the first portion.